Brooks, 42, also conceded that he sent digital files over the Internet via a file sharing Web site to an undercover FBI agent, saying the files included another pornographic video showing an adult sexually assaulting a child.

He will face from 15 to 50 years in prison when he is sentenced this summer, according to a plea agreement with Brooklyn federal prosecutors.

Brooks was on the staff at the Brooklyn public school – also referred to as “The Weeksville School” – for nearly two decades until FBI agents arrested him early last year.

The feds discovered more than 1,000 digital files of children as young as 10 posing in explicit photos during a search of his house.

Those developments prompted an aggressive FBI probe and eventually led investigators to believe that Brooks was molesting school children entrusted to his care, after they found child porn videos on his computer hard drive that were filmed inside several classrooms.

Agents interviewed teachers, school staff, parents, and children, in an effort to determine the extent of Brooks’ alleged damage.

City Schools Chancellor Dennis Walcott also visited the elementary school, and the school’s principal called the molestation allegations “deeply troubling news.”

The former school staffer is still awaiting trial in separate criminal case leveled by the Brooklyn District Attorney’s Office, charging him with two counts of sexual contact with a child and one count of endangering the welfare of a minor.

Brooks, who earned $37,000 a year as a teacher’s aide, was assigned to a small, special-education classroom with one teacher and 12 kids at the school.

A disquieting photograph posted on Brooks’ blog on the elementary school’s Web site showed him dressed as the Easter Bunny and surrounded by young children in a playground.